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#ifndef MESSAGE_FILTERS__SIMPLE_FILTER_HPP_
#define MESSAGE_FILTERS__SIMPLE_FILTER_HPP_

#include <functional>
#include <memory>
#include <string>

#include "message_filters/connection.hpp"
#include "message_filters/signal1.hpp"
#include "message_filters/message_event.hpp"

namespace message_filters
{

/**
 * \brief Convenience base-class for simple filters which output a single message
 *
 * SimpleFilter provides some of the tricky callback registering functionality, so that
 * simple filters do not have to duplicate it.  It also provides getName()/setName() for debugging
 * purposes.
 */
template<class M>
class SimpleFilter : public noncopyable
{
public:
  typedef std::shared_ptr<M const> MConstPtr;
  typedef std::function<void (const MConstPtr &)> Callback;
  typedef MessageEvent<M const> EventType;
  typedef std::function<void (const EventType &)> EventCallback;

  /**
   * \brief Register a callback to be called when this filter has passed
   * \param callback The callback to call
   */
  template<typename C>
  Connection registerCallback(const C & callback)
  {
    typename CallbackHelper1<M>::Ptr helper = signal_.addCallback(Callback(callback));
    return Connection(std::bind(&Signal::removeCallback, &signal_, helper));
  }

  /**
   * \brief Register a callback to be called when this filter has passed
   * \param callback The callback to call
   */
  template<typename P>
  Connection registerCallback(const std::function<void(P)> & callback)
  {
    return Connection(std::bind(&Signal::removeCallback, &signal_, signal_.addCallback(callback)));
  }

  /**
   * \brief Register a callback to be called when this filter has passed
   * \param callback The callback to call
   */
  template<typename P>
  Connection registerCallback(void (* callback)(P))
  {
    typename CallbackHelper1<M>::Ptr helper =
      signal_.template addCallback<P>(std::bind(callback, std::placeholders::_1));
    return Connection(std::bind(&Signal::removeCallback, &signal_, helper));
  }

  /**
   * \brief Register a callback to be called when this filter has passed
   * \param callback The callback to call
   */
  template<typename T, typename P>
  Connection registerCallback(void (T::* callback)(P), T * t)
  {
    typename CallbackHelper1<M>::Ptr helper =
      signal_.template addCallback<P>(std::bind(callback, t, std::placeholders::_1));
    return Connection(std::bind(&Signal::removeCallback, &signal_, helper));
  }

  /**
   * \brief Set the name of this filter.  For debugging use.
   */
  void setName(const std::string & name) {name_ = name;}
  /**
   * \brief Get the name of this filter.  For debugging use.
   */
  const std::string & getName() {return name_;}

protected:
  /**
   * \brief Call all registered callbacks, passing them the specified message
   */
  void signalMessage(const MConstPtr & msg)
  {
    MessageEvent<M const> event(msg);

    signal_.call(event);
  }

  /**
   * \brief Call all registered callbacks, passing them the specified message
   */
  void signalMessage(const MessageEvent<M const> & event)
  {
    signal_.call(event);
  }

private:
  typedef Signal1<M> Signal;

  Signal signal_;

  std::string name_;
};

}  // namespace message_filters

#endif  // MESSAGE_FILTERS__SIMPLE_FILTER_HPP_
